<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Flexbox 布局</title>
  <style>
    .container {
      display: flex;
      justify-content: space-between;
    }

    .item {
      background-color: #f0f0f0;
      padding: 20px;
      width: 30%;
    }
  </style>
</head>

<body>
  <div class="container">
    <div class="item">项目 1</div>
    <div class="item">项目 2</div>
    <div class="item">项目 3</div>
  </div>
</body>

</html>